Abstract: A casing treatment comprising a hub having a surface, the hub being rotatable about an axis within a casing of a gas turbine engine compressor, at least one spiral groove formed in the surface extending axially relative to the axis, a stator blade fixed to the casing, wherein a tip of the stator blade is proximate to the at least one spiral groove.

Abstract: A variable vane assembly may comprise a first vane and a second vane. The first vane may comprise a first strut portion and a first flap portion. The first flap portion may be configured to pivot relative to the first strut portion. The second vane may comprise a second strut portion and a second flap portion. The second flap portion may be configured to pivot relative to the second strut portion. The first flap may be configured to pivot independently of the second flap.

Abstract: A morphing aerodynamic control surface geometry comprising a control surface having an articulated portion comprising a flexible skin coupled at an exterior of the articulated portion, the flexible skin comprising opposed interlocking elements sandwiched within a flexible polymer coupled to the interlocking elements; wherein the flexible skin is configured compliant responsive to an articulation of the articulated portion.

Abstract: Disclosed is a flutter damper, including an acoustic liner configured for peak acoustical energy absorption at a frequency range that is greater than a frequency range associated with fan flutter, a chamber, and a piezoelectric element disposed within a first surface of the chamber, and the chamber being configured for peak acoustical energy absorption at a frequency range that is associated with one or more fan flutter modes, and wherein the piezoelectric element is operatively connected to an electronic engine control.

Abstract: Disclosed is a flutter damper including a first plurality of chambers configured for peak acoustical energy absorption at a frequency range that is associated with a first fan flutter mode, the first plurality of chambers in fluid communication with a flow surface, and a second plurality of chambers configured for peak acoustical energy absorption at a frequency range that is associated with a second fan flutter mode, the second plurality of chambers in fluid communication with the flow surface, and wherein the first plurality of chambers and second plurality of chambers are disposed in a grid pattern.

Abstract: Disclosed is a flutter damper, including an acoustic liner configured for peak acoustical energy absorption at a frequency range that is greater than a frequency range associated with fan flutter, a chamber, and a piezoelectric element disposed within a first surface of the chamber, and the chamber being configured for peak acoustical energy absorption at a frequency range that is associated with one or more fan flutter modes, and wherein the piezoelectric element is operatively connected to an electronic engine control.

Abstract: A computer-implemented method for designing a built-in test is described. The method includes receiving, via a processor, a subsystem model including system parameters for a heat exchanger, wherein each of the system parameters includes a sensor variance; determining, via the processor, a test design vector based on one or more of the system parameters; and designing, via the processor, the built-in test based on the test design vector.

Abstract: A particle separation device to remove particulate matter from an exterior air flow for use with an environmental control system includes a curved airflow path with an inner radius and an outer radius, the curved air flow path to receive the exterior air flow, a particle passage disposed along at least one of the inner radius and the outer radius to receive the particulate matter from the exterior air flow, a circumferential volute to receive the particulate matter from the particle passage, and a duct to transport the particulate matter from the circumferential volute to a downstream region.

Abstract: In accordance with one aspect of the disclosure, a rotor for a gas turbine engine is disclosed. The rotor may include a rotor disk and a plurality of blade extending radially outward from the rotor disk. At least one of the blades may have a physical nonuniformity. The blades may be distributed about the rotor disk based on any physical nonuniformities of the blades to generate at least one decay-resistant harmonic.

Abstract: Disclosed is a flutter damper including a first plurality of chambers configured for peak acoustical energy absorption at a frequency range that is associated with a first fan flutter mode, the first plurality of chambers in fluid communication with a flow surface, and a second plurality of chambers configured for peak acoustical energy absorption at a frequency range that is associated with a second fan flutter mode, the second plurality of chambers in fluid communication with the flow surface, and wherein the first plurality of chambers and second plurality of chambers are disposed in a grid pattern.

Abstract: Disclosed is a flutter damper, including an acoustic liner configured for peak acoustical energy absorption at a frequency range that is greater than a frequency range associated with fan flutter, a chamber, and a piezoelectric element disposed within a first surface of the chamber, and the chamber being configured for peak acoustical energy absorption at a frequency range that is associated with one or more fan flutter modes, and wherein the piezoelectric element is operatively connected to an electronic engine control.

Abstract: A gas turbine engine includes an engine core having a compressor section, a combustor fluidly connected to the compressor section, and a turbine section fluidly connected to the combustor section. At least one compressor bleed connects a compressor flowpath with a first cooled cooling air path. The first cooled cooling air path includes a supplementary coolant injector connected to a supplementary coolant supply. The cooled cooling air path including a portion exterior to the engine core.

Abstract: A gas turbine engine has a propulsor including a fan and a liner positioned upstream of the fan. The liner has a backing plate, a cellular structure with cells extending from the backing plate, and a perforated sheet with a depth defined as a distance between the perforated sheet and the backing sheet. The depth is selected to achieve a desired ratio of the depth relative to a gap?. A depth to gap ratio is substantially in a range of 0.035 to 0.08. A method is also disclosed.

Abstract: A water separator comprises an axially extending airflow passage, an airflow mixer, a plurality of electric plates of alternating charge, and a mechanical separator. The airflow mixer, the plurality of electric plates, and the mechanical separator are disposed within the airflow passage. The airflow mixer imparts a non-axial flow component on airflow through the airflow passage. The electric plates are situated downstream of the mixer, and create an electric field region within the airflow passage. The mechanical separator is situated at or downstream of the electric field region, and is disposed to separate water droplets from air.

Abstract: A particle separation device to remove particulate matter from an exterior air flow for use with an environmental control system includes a curved airflow path with an inner radius and an outer radius, the curved air flow path to receive the exterior air flow, a particle passage disposed along at least one of the inner radius and the outer radius to receive the particulate matter from the exterior air flow, a circumferential volute to receive the particulate matter from the particle passage, and a duct to transport the particulate matter from the circumferential volute to a downstream region.

Abstract: A water separator comprises an axially extending airflow passage, an airflow mixer, a plurality of electric plates of alternating charge, and a mechanical separator. The airflow mixer, the plurality of electric plates, and the mechanical separator are disposed within the airflow passage. The airflow mixer imparts a non-axial flow component on airflow through the airflow passage. The electric plates are situated downstream of the mixer, and create an electric field region within the airflow passage. The mechanical separator is situated at or downstream of the electric field region, and is disposed to separate water droplets from air.

Abstract: A computer-implemented method for designing a built-in test is described. The method includes receiving, via a processor, a subsystem model including system parameters for a heat exchanger, wherein each of the system parameters includes a sensor variance; determining, via the processor, a test design vector based on one or more of the system parameters; and designing, via the processor, the built-in test based on the test design vector.

Abstract: A fan rotor for an aircraft environmental control system ram fan is provided. The fan rotor includes central body defining a central axis and a radius having a first radial distance that is defined as a distance from the central axis to an edge of the central body. A plurality of fan blades extend radially from the edge of the central body to a second radial distance, the second radial distance defined as a distance from the central axis to a tip of the fan blades. A shroud extends circumferentially between and connecting each of the plurality of fan blades. The shroud is located at a radial distance from the central axis that is greater than the first radial distance and includes one or more tuning features configured to mistune a vibration of the fan rotor during operation.

Abstract: In accordance with one aspect of the disclosure, a rotor for a gas turbine engine is disclosed. The rotor may include a rotor disk and a plurality of blade extending radially outward from the rotor disk. At least one of the blades may have a physical nonuniformity. The blades may be distributed about the rotor disk based on any physical nonuniformities of the blades to generate at least one decay-resistant harmonic.

Abstract: A gas turbine engine has a propulsor including a fan and a liner positioned upstream of the fan. The liner has a backing plate, a cellular structure with cells extending from the backing plate, and a perforated sheet with a depth defined as a distance between the perforated sheet and the backing sheet. The depth is selected to achieve a desired ratio of the depth relative to a gap?. A depth to gap ratio is substantially in a range of 0.035 to 0.08. A method is also disclosed.